diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,4 +1,11 @@
 
+= lensref-0.2 =
+
+* Do not always build tests
+* 'cabal test' support
+* Eliminate dependency on lens, operational and containers packages
+* Add lower bound to transformers package dependency
+
 = lensref-0.1.0.5 =
 
 another bugfix for hackagedb
diff --git a/lensref.cabal b/lensref.cabal
--- a/lensref.cabal
+++ b/lensref.cabal
@@ -1,5 +1,5 @@
 name:               lensref
-version:            0.1.0.5
+version:            0.2
 category:           Control, Data
 synopsis:           References which can be joined and on which lenses can be applied
 description:
@@ -43,7 +43,7 @@
 homepage:           http://www.haskell.org/haskellwiki/LGtk
 bug-reports:        https://github.com/divipp/lensref/issues
 maintainer:         divipp@gmail.com
-cabal-version:      >= 1.8
+cabal-version:      >= 1.9.2
 build-type:         Simple
 extra-source-files: changelog
 
@@ -51,35 +51,36 @@
   type:             git
   location:         https://github.com/divipp/lensref.git
 
-Flag Pure
-  Description:      Use the pure but slow implementation
+Flag tests
+  Description:      Build the tests
   Default:          False
 
-
 library
 
   hs-source-dirs:
                     src
   build-depends:
                     base < 5
-                  , transformers < 0.5
+                  , transformers >= 0.3 && < 0.5
                   , mtl < 2.3
                   , monad-control < 0.4
-                  , operational < 0.3
-                  , lens < 4.2
-                  , containers < 0.6
-
   exposed-modules:
                     Data.LensRef
                     Data.LensRef.Common
-                    Data.LensRef.TestEnv
-                    Data.LensRef.Test
                     Data.LensRef.Pure
                     Data.LensRef.Fast
-                    Data.LensRef.Default
-  if flag(Pure)
+  other-modules:
+                    Control.Lens.Simple
+  if flag(tests)
     cpp-options:
-                    -D__PURE__
+                    -D__TESTS__
+    build-depends:
+                    operational < 0.3
+                  , containers < 0.6
+                  , lens < 4.2
+    exposed-modules:
+                    Data.LensRef.TestEnv
+                    Data.LensRef.Test
 
   ghc-options: 
                     -Wall 
@@ -88,4 +89,13 @@
                     -fno-warn-missing-signatures 
                     -fno-warn-orphans
                     -fno-warn-type-defaults
+
+test-suite runtests
+
+  type:             exitcode-stdio-1.0
+  main-is:          runtests.hs
+  build-depends:
+                    base < 5
+                  , lensref
+
 
diff --git a/runtests.hs b/runtests.hs
new file mode 100644
--- /dev/null
+++ b/runtests.hs
@@ -0,0 +1,10 @@
+module Main where
+
+import qualified Data.LensRef.Pure as Pure
+import qualified Data.LensRef.Fast as Fast
+
+main :: IO ()
+main = do
+    Pure.runTests
+    Fast.runTests
+
diff --git a/src/Control/Lens/Simple.hs b/src/Control/Lens/Simple.hs
new file mode 100644
--- /dev/null
+++ b/src/Control/Lens/Simple.hs
@@ -0,0 +1,63 @@
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE NoMonomorphismRestriction #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE FunctionalDependencies #-}
+{-# LANGUAGE FlexibleInstances #-}
+-- | Minimalized lens dependency. Compatible with the lens package.
+module Control.Lens.Simple where
+
+import Control.Applicative
+import Control.Monad.Identity
+import Control.Monad.Reader
+import Control.Monad.State
+
+-----------
+
+type Lens s t a b = forall f. Functor f => (a -> f b) -> s -> f t
+
+type Lens' s a = Lens s s a a
+
+lens :: (s -> a) -> (s -> b -> t) -> Lens s t a b
+lens sa sbt afb s = sbt s <$> afb (sa s)
+
+set :: Lens s t a b -> b -> s -> t
+set l s = runIdentity . l (const $ Identity s)
+
+united :: Lens' a ()
+united f v = fmap (\() -> v) $ f ()
+
+infixl 8 ^.
+
+(^.) :: a -> Lens' a b -> b
+a ^. l = getConst $ l Const a
+
+view :: MonadReader s m => Lens' s a -> m a
+view l = asks (^. l)
+
+(.=) :: MonadState s m => Lens' s a -> a -> m ()
+l .= a = modify $ set l a
+
+magnify :: Monad m => Lens' a b -> ReaderT b m c -> ReaderT a m c
+magnify l (ReaderT f) = ReaderT $ \a -> f $ a ^. l
+
+class Field1 s t a b | s -> a, t -> b, s b -> t, t a -> s where
+    _1 :: Lens s t a b
+
+instance Field1 (a,b) (a',b) a a' where
+  _1 k ~(a,b) = k a <&> \a' -> (a',b)
+
+infixl 1 <&>
+
+(<&>) :: Functor f => f a -> (a -> b) -> f b
+as <&> f = f <$> as
+
+class Field2 s t a b | s -> a, t -> b, s b -> t, t a -> s where
+    _2 :: Lens s t a b
+
+instance Field2 (a,b) (a,b') b b' where
+  _2 k ~(a,b) = k b <&> \b' -> (a,b')
+
+instance Field2 (a,b,c,d) (a,b',c,d) b b' where
+  _2 k ~(a,b,c,d) = k b <&> \b' -> (a,b',c,d)
+
+
diff --git a/src/Data/LensRef.hs b/src/Data/LensRef.hs
--- a/src/Data/LensRef.hs
+++ b/src/Data/LensRef.hs
@@ -50,7 +50,7 @@
 
 import Control.Monad
 import Control.Monad.Identity
-import Control.Lens (Lens', set, united)
+import Control.Lens.Simple (Lens', set, united)
 
 --------------------------------
 
diff --git a/src/Data/LensRef/Default.hs b/src/Data/LensRef/Default.hs
deleted file mode 100644
--- a/src/Data/LensRef/Default.hs
+++ /dev/null
@@ -1,15 +0,0 @@
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE RankNTypes #-}
--- | Default implementation. Points to either to the pure or the fast implementation depending on the cabal flag @PURE@.
-module Data.LensRef.Default
-    ( Register
-    , runRegister
-    ) where
-
-#ifdef __PURE__
-import Data.LensRef.Pure
-#else
-import Data.LensRef.Fast
-#endif
-
-
diff --git a/src/Data/LensRef/Fast.hs b/src/Data/LensRef/Fast.hs
--- a/src/Data/LensRef/Fast.hs
+++ b/src/Data/LensRef/Fast.hs
@@ -6,6 +6,7 @@
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE NoMonomorphismRestriction #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE CPP #-}
 --{-# OPTIONS_HADDOCK hide #-}
 {- |
 Fast implementation for the @MonadRefCreator@ interface.
@@ -25,12 +26,14 @@
 import Control.Applicative hiding (empty)
 import Control.Monad.State
 import Control.Monad.Reader
-import Control.Lens
+import Control.Lens.Simple
 
 import Data.LensRef
 import Data.LensRef.Common
+#ifdef __TESTS__
 import Data.LensRef.TestEnv
 import Data.LensRef.Test
+#endif
 
 ----------------------
 
@@ -290,6 +293,7 @@
 
 --------------------------
 
+#ifdef __TESTS__
 instance MonadRegisterRun (Register (Prog TP)) where
 
     type AsocT (Register (Prog TP)) = TP
@@ -298,6 +302,7 @@
 
 newtype TP = TP { unTP :: Wrap (Prog TP) () }
 
+runTests :: IO ()
 runTests = do
     mkTests runTestSimple
     tests runTest
@@ -308,4 +313,8 @@
 
 runTestSimple :: Register (Prog TP) () -> IO ()
 runTestSimple m = runTest "" m $ return ((), return ())
+#else
+runTests :: IO ()
+runTests = fail "enable the tests flag like \'cabal configure --enable-tests -ftests; cabal build; cabal test\'"
+#endif
 
diff --git a/src/Data/LensRef/Pure.hs b/src/Data/LensRef/Pure.hs
--- a/src/Data/LensRef/Pure.hs
+++ b/src/Data/LensRef/Pure.hs
@@ -8,6 +8,7 @@
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE StandaloneDeriving #-}
 {-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE CPP #-}
 -- {-# OPTIONS_HADDOCK hide #-}
 {- |
 Register reference implementation for the @MonadRefCreator@ interface.
@@ -24,17 +25,16 @@
 import Control.Applicative
 import Control.Monad.State
 import Control.Monad.Reader
-import Control.Arrow (second)
-import qualified Data.Sequence as Seq
-import Control.Lens hiding ((|>))
-import Data.Foldable (toList)
+import Control.Lens.Simple
 
 import Unsafe.Coerce
 
 import Data.LensRef
 import Data.LensRef.Common
+#ifdef __TESTS__
 import Data.LensRef.TestEnv
 import Data.LensRef.Test
+#endif
 
 ----------------------
 
@@ -44,12 +44,12 @@
 
 ----------------------
 
-newtype Lens_ a b = Lens_ {unLens_ :: ALens' a b}
+newtype Lens_ a b = Lens_ {unLens_ :: Lens' a b}
 
 runLens_ :: Reader a (Lens_ a b) -> Lens' a b
-runLens_ r f a = cloneLens (unLens_ $ runReader r a) f a
+runLens_ r f a = unLens_ (runReader r a) f a
 
-type LSt = Seq.Seq CC
+type LSt = [CC]
 
 data CC = forall a . CC (LSt -> a -> a) a
 
@@ -70,7 +70,7 @@
 instance RefClass (Lens_ LSt) where
     type RefReaderSimple (Lens_ LSt) = Reader LSt
 
-    readRefSimple = view . runLens_
+    readRefSimple r = view $ runLens_ r
     writeRefSimple r a = runLens_ r .= a
     lensMap l r = return $ Lens_ $ runLens_ r . l
     unitRef = return $ Lens_ united
@@ -86,13 +86,13 @@
         rk = set (runLens_ r) . (^. r2)
         kr = set r2 . (^. runLens_ r)
 
-        extend x0 = (return $ Lens_ $ lens get set, x0 Seq.|> CC kr (kr x0 a0))
+        extend x0 = (return $ Lens_ $ lens get set, x0 ++ [CC kr (kr x0 a0)])
           where
-            limit = second toList . Seq.splitAt (Seq.length x0)
+            limit = splitAt (length x0)
 
             get = unsafeData . head . snd . limit
 
-            set x a = foldl (\x -> (Seq.|>) x . ap_ x) (rk a zs Seq.|> CC kr a) ys where
+            set x a = foldl (\x -> (x++) . (:[]) . ap_ x) (rk a zs ++ [CC kr a]) ys where
                 (zs, _ : ys) = limit x
 
         ap_ :: LSt -> CC -> CC
@@ -251,6 +251,7 @@
 
 ------------------------
 
+#ifdef __TESTS__
 instance MonadRegisterRun (Register (Prog TP)) where
 
     type AsocT (Register (Prog TP)) = TP
@@ -259,6 +260,7 @@
 
 newtype TP = TP { unTP :: SLSt (Prog TP) () }
 
+runTests :: IO ()
 runTests = do
     mkTests runTestSimple
     tests runTest
@@ -269,6 +271,8 @@
 
 runTestSimple :: Register (Prog TP) () -> IO ()
 runTestSimple m = runTest "" m $ return ((), return ())
-
-
+#else
+runTests :: IO ()
+runTests = fail "enable the tests flag like \'cabal configure --enable-tests -ftests; cabal build; cabal test\'"
+#endif
 
diff --git a/src/Data/LensRef/TestEnv.hs b/src/Data/LensRef/TestEnv.hs
--- a/src/Data/LensRef/TestEnv.hs
+++ b/src/Data/LensRef/TestEnv.hs
@@ -244,12 +244,15 @@
     -> tm a
     -> Prog' (a, Prog' ())
     -> IO ()
-runTest_ name lift runRegister_ r p0 = putStr $ unlines $ handEr name $ flip evalStateT (ST [] [] 0 Seq.empty) $ do
+runTest_ name lift runRegister_ r p0 = showError $ handEr name $ flip evalStateT (ST [] [] 0 Seq.empty) $ do
     (Just (a1,c),pe) <- coeval_ lift (runRegister_ (singleton ReadI) (singleton . WriteI) r) p0
     (a2,p) <- getProg' pe
     when (a1 /= a2) $ fail' $ "results differ: " ++ show a1 ++ " vs " ++ show a2
     (_, pr) <- coeval_ lift c p
     getProg' pr
+
+showError [] = return ()
+showError xs = fail $ "\n" ++ unlines xs
 
 ------------------------------------------------